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Current state-of-the-art vehicles implement pedestrian protection features that rely on pedestrian detection sensors and algorithms to trigger when impacting a pedestrian. During the development phase, the vehicle must “learn” to discriminate pedestrians from the rest of potential impacting objects. Part of the training data used in this process is often obtained in physical tests utilizing legform impactors whose external biofidelity is still to be evaluated. This study uses THUMS as a reference to assess the external biofidelity of the most commonly used impactors (Flex-PLI, PDI-1 and PDI-2). This biofidelity assessment was performed by finite element simulation measuring the bumper beam forces exerted by each surrogate on a sedan and a SUV. The bumper beam was divided in 50 mm sections to capture the force distribution in both vehicles. This study, unlike most of the pedestrian-related literature, examines different impact locations and velocities.

Power steering systems provide significant design challenges. They are detrimental to fuel economy since most require the continuous operation of a hydraulic pump. This generates heat that must be dissipated by fluid lines and heat exchangers. This paper presents a simple one-dimensional transient model for power steering components. The model accounts for the pump power, heat dissipation from fluid lines, the power steering cooler, and the influence of radiation heat from exhaust system components. The paper also shows how to use a transient thermal model of the entire system to simulate the temperatures during cyclic operation of the system. The implications to design, drive cycle simulation, and selection of components are highlighted.

Gasoline Compression Ignition (GCI) has been identified as a technology which could give both high efficiency and relatively low engine-out emissions. The introduction of any new vehicle technology requires widespread availability of appropriate fuels. It would be ideal therefore if GCI vehicles were able to operate using the standard grade of gasoline that is available at the pump. However, in spite of recent progress, operation at idle and low loads still remains a formidable challenge, given the relatively low autoignition reactivity of conventional gasoline at these conditions. One conceivable solution would be to use both diesel and gasoline, either in separate tanks or blended as a single fuel (“dieseline”). However, with this latter option, a major concern for dieseline would be whether a flammable mixture could exist in the vapour space in the fuel tank.

Fuels are subjected to extreme conditions inside a fuel injector. In modern common rail diesel engines, fuel temperatures can reach 150°C and pressures can exceed 2500 bar inside the rail. Under such conditions the fluid physical properties of the fuel can differ substantially from ambient pressure and temperature and can impact the spray behavior and characteristics. Moreover, experimental determination of the fuel physical properties at these extreme conditions can be very difficult. Previously it has been shown that for pure components, all atom molecular simulations offer a reliable means to calculate the key physical properties (including transport properties, e.g., viscosity) at FIE representative conditions. In this study we extend the approach to calculate these properties of binary mixtures using atomistic molecular simulations.

There is a growing demand for ethanol fuel for which attention is being paid as an alternative fuel for petroleum from the standpoint of CO2 reduction and fuel economy. Especially in Brazil under the government policy of bio-fuel promotion, the regular gasoline containing 20% of alcohol and 100% alcohol are being sold, requiring a system that can cope with a high-alcohol-content fuel mixing the aforementioned fuels. As the dusts in the fuel disperse in the form of fine particles because the high-alcohol-content fuel has a high affinity, the amount of dust that passes through the fuel filter increases. At the same time, there was such a concern that the pump case, which was composed of the pump cover and the pump housing, wore and reduced fuel flow as the amount of dust that entered the fuel feed pump (hereafter referred to as FFP) increased.

The advanced development and optimization of fuel atomization in port and direct injection systems for automobile engine is desired for the improvement of fuel combustion performance and thermal efficiency of the engine. Computational prediction and design of injector nozzle spray flow is an effective method for that. However, a practical simulation method of the continuous primary, secondary spray breakups and the spraying behavior have not been developed yet. In this study, we have developed the integrated computational method of the total fuel atomization process of the injector nozzle. This new computational approach is taking into account the nozzle internal flow to form the primary breakup using Volume of Fluid (VOF) method in connection with the spray flow characteristics to the engine cylinder using Discrete Droplet Model (DDM).

Government regulations and market demands continue to emphasize conservation of fossil fuels in the transportation industry. As a consequence, any incremental improvement in fuel economy (FE) is of great importance in the automotive sector. For instance, lower viscosity lubricants have been shown to improve FE but the longevity of such improvement is compromised by viscosity increases often observed as a lubricant ages during an oil drain interval (ODI). To address this issue, an option to manage lubricant viscometrics via fuel is proposed. In order to investigate such mitigation of viscosity increase during an ODI, and potentially the delivery of an ODI-averaged FE benefit, a fleet test was conducted with a fuel-borne additive intended to control increases in lubricant viscosity. The fleet test compared a market-representative reference fuel to a fuel containing a viscosity control additive (VCA).

We propose to enhance reliability based diagnosis by enhancing the fault tree model with a sensor layer for capturing evidence. We recognized the need for an automated diagnostic process that can predict and report component failure in vehicles prior to total failure of any system in the vehicle. We also want to take advantage of evidence that can be derived from sensors to reduce the amount of tests required to identify failed components.

The electrochemical and corrosion behavior of metals in aqueous environments has received substantial attention. However, relatively little work has been devoted to the electrochemistry and corrosion of metals in non-aqueous environments. Now, with greater pressures to increase fuel efficiencies and decrease exhaust emissions, alternatives and additives to gasoline (including methanol and ethanol) are receiving increased attention from government agencies and automobile manufacturers. Unfortunately, fundamental studies of the corrosion behavior of metals in these solutions are scarce. The objective of the present work is to investigate the electrochemical and corrosion behavior of iron in methanolic solutions containing Cl, H+, SO42-, and H2O. To accomplish this, a full factorial design test matrix was developed to systematically evaluate the effects of these impurities on the corrosion behavior of iron.

The University of Virginia is investigating the use of a magnetohydrodynamic (MHD) angular rate sensor to measure head angular acceleration in impact testing. Output from the sensor, which measures angular velocity, must be differentiated to produce angular acceleration. As a precursor to their use in actual testing, a torsional pendulum was developed to analyze an MHD sensor's effectiveness in operating under impact conditions. Differentiated and digitally filtered sensor data provided a good match with the vibratory response of the pendulum for various magnitudes of angular acceleration. Subsequent head drop tests verified that MHD sensors are suitable for measuring head angular acceleration in impact testing.

Pedestrian impact protection has been a growing area of research over the past twenty or more years. The results from many studies have shown the importance of providing protection to vulnerable road users as a means of reducing roadway fatalities. Most of this research has focused on the vehicle fleet as a whole in datasets that are dominated by passenger cars (cars). Historically, the influence of vehicle body type on injury distribution patterns for pedestrians has not been a primary research focus. In this study we used the Pedestrian Crash Data Study (PCDS) database of detailed pedestrian crash investigations to identify how injury patterns differ for pedestrians struck by light trucks, vans, and sport utility vehicles (LTVs) from those struck by cars. AIS 2+ and 3+ injuries for each segment of vehicles were mapped back to both the body region of the pedestrian injured and the vehicle source linked to that injury in the PCDS database.

This paper explains the new methodology for post-crash fuel leakage testing of Fuel Cell Vehicles (FCVs) and other hydrogen vehicles utilizing compressed hydrogen storage systems. This methodology was incorporated into SAE J2578 that was revised and published in January, 2009. The new methodology is based on the concept in FMVSS 303 that specifies post-crash fuel leakage test method and criteria for CNG vehicle and adopted some modifications. Specifically, the following items are addressed: (1) Allowable leakage can be accurately evaluated in test even with large size tank that obtains only small pressure drop when a given amount of leakage occurs. A new method to deal with the influence of measurement errors was devised. (2) Even though only one option of test gas and initial filling pressure is accepted in FMVSS 303, new methodology for hydrogen system allows helium and hydrogen at reduced pressure as alternatives in addition to hydrogen at service pressure.

The effect of fuel sulphur on emissions from a lean-burn G-DI passenger car homologated according to German D3 specifications was investigated over the European drive cycles. In addition some tests over US Federal cycles were conducted. No statistically significant deterioration in tailpipe emissions was detected with the leanburn G-DI technology using a selective reduction type de-NOx catalyst at fuel sulphur levels from 30 to 300 mg/kg. The emission response to fuel sulphur level was essentially flat, and the sulphur effect was less than that seen in the EPEFE fleet. Tests were conducted applying a rigorous test protocol including four repeats with each fuel and a desulphation procedure between fuel changes. Approximately 15-20% improvement in fuel economy over comparable MPI cars was predicted based on the CO2 results from the current programme and German type approval data. Increased particulate mass emissions were observed, compared with typical MPI cars.

Low Temperature Combustion using compression ignition may provide high efficiency combined with low emissions of oxides of nitrogen and soot. This process is facilitated by fuels with lower cetane number than standard diesel fuel. Mixtures of gasoline and diesel (“dieseline”) may be one way of achieving this; however, a gasoline/diesel mixture in a fuel tank can result in a flammable headspace, particularly at very cold ambient temperatures. A mathematical model to predict the flammability of dieseline blends, including those containing ethanol, was previously validated. In this paper, that model is used to study the flammability of dieseline blends parametrically. Gasolines used in the simulations had Dry Vapour Pressure Equivalent (DVPE) values of 45, 60, 75, 90 and 110 kPa.

The application of optical diagnostics in turbulent reactive flows often suffers from the beam steering (BS) effects, resulting in degraded image quality and/or measurement accuracy. This work investigated a method to correct the BS effects to improve the accuracy of optical diagnostics, with particle imagine velocimetry (PIV) measurements on turbulent reactive flames as an example. The proposed method used a guiding laser to correct BS. Demonstration in laboratory turbulent flames showed promising results where the accuracy of PIV measurement was significantly enhanced. Applicability to more complicated and practical situations are discussed.

A follow-up case study on rollover testing with a single full-size sport utility vehicle (SUV) was conducted under controlled real-world conditions. The purpose of this study was to conduct a well-documented rollover event that could be utilized in evaluating various methods and techniques over the phases associated with rollover accidents. The phases documented and discussed, inherent to rollovers, are: pre-trip, trip, and rolling phases. With recent advances in technology, new devices and techniques have been designed which improve the ability to capture and document the unpredictable dynamic events surrounding vehicle rollovers. One such device is an inertial measurement unit (IMU), which utilizes GPS technology along with integrated sensors to report and record measured dynamic parameters real-time. The data obtained from a RT-4003 IMU device are presented and compared along with previous test data and methodology.

To address challenges related to refueling with compressed hydrogen, a simple, analytical method has been developed that allows a hydrogen station to directly and accurately calculate an end-of-fill temperature in a hydrogen tank and thereby maximize the fill quantity and minimize the refueling time. This is referred to as the MC Fueling Method, where MC represents total heat capacity. The MC Method incorporates a set of thermodynamic parameters for the tank system that are used by the station in a simple analytical equation along with measured values of dispensed hydrogen temperature and pressure at the station. These parameters can be communicated to the hydrogen station either directly from the vehicle or from a database that is accessible by the station. Because the MC Method is based on direct measurements of actual thermodynamic conditions at the station, and quantified thermodynamic behavior of the tank system, highly accurate tank filling results can be achieved.

A second-generation power control unit (PCU) for a two-motor hybrid system is proposed. An optimally designed power module, which is a key component of the PCU, is applied to increase heat-resistant temperature, while the basic structure of the first generation is retained and the power semiconductor chip is directly cooled from the single side. In addition to the optimum design, by decreasing the power loss as well as increasing the heat-resistant temperature of the power semiconductors (IGBT: Insulated Gate Bipolar Transistor and FWD: Free Wheeling Diode), the proposed PCU has attained 25% higher power density and 23% smaller size compared to first-generation units, maintaining PCU efficiency (fuel economy). To achieve a high yield rate in the power module assembly process, a new screening technology is adopted at the initial stage of power module manufacturing.

As accurate measuring of head accelerations is an important aspect in predicting head injury, it is important that the measuring sensor be well-coupled to the head. Various sensors and sensor mounting schemes have been attempted in the past with varying results. This study uses a small, implantable acceleration sensor pack in the ear to study impact coupling with the human skull. The output from these ear-mounted accelerometers is compared to laboratory reference accelerometers rigidly attached to the skull of two cadaveric head specimens for both low-amplitude oscillatory tests and high-amplitude impact drop tests. The combination of sensor type and mounting scheme demonstrates the feasibility of using ear mounted sensors to predict head acceleration response. Previously reported progressive phase lag was not seen in this study, with the comparison between ear mounted accelerometers and rigidly mounted head accelerometers ranging from very good to excellent.

Given the increased use of programmable embedded electronic systems (PEES) in automotive applications and their vital importance, it is not only important for engineers to design PEES in such a way to meet or exceed safety requirements but also quantify how “safe” these systems are. At the University of Virginia's Center for Safety-Critical Systems, we have developed a safety quantification methodology for embedded real time safety-related systems. The goal of the safety quantification methodology is to provide a generic but rigorous and systematic way of characterizing the dependability behavior of embedded systems that is applicable to a broad range of applications from automotive to nuclear. This paper presents a quantitative safety assessment methodology for safety-critical embedded systems using fault injection (FI). This methodology has been developed, refined and applied to a number of commercial safety-grade systems in the railway, nuclear and avionics industries.